“Through-the-glass”, double-sided laser crystallisation using copper vapour lasers for the production of thin film silicon material

Through-the-glass laser crystallisation of a-Si, on low-temperature glass, has been achieved for the first time using a copper vapour laser (CVL). The CVLʹs 578/511 nm output has minimal absorption in the substrate, thus allowing a simple double-sided irradiation regime. Raman spectroscopy showed that double-sided irradiation is more effective at producing full depth crystallisation, and incrementally increases the crystallisation depth with each pulse. A step-wise crystallisation concept is also introduced to explain the incremental crystallisation behaviour. Additionally, grain sizes were maintained without the need for substrate heating. These factors enhance the CVLʹs potential to simplify producing PV materials via laser crystallisation.